In recent years, touch panels which enable users to make intuitive manipulations have come to be used as devices for receiving input manipulations on electronic device including cellphones. Touch panels are known as devices which enable, through the same screen of an electronic device, an input manipulation on the screen and display processing for a processing result of the electronic device. It is an important issue how to fill the gap between the accuracy with which an electronic device can perform processing on a touch panel and the input accuracy that is expected by users.
The gap between the accuracy with which an electronic device can perform processing and the input accuracy expected by users will be described with reference to FIGS. 15(a) and 15(b). FIG. 15(a) shows lists of news headlines displayed on the screen of an electronic device incorporating a touch panel. FIG. 15(b) shows how characters are input through the screen of the electronic device incorporating the touch panel.
As shown in FIG. 15(a), the user can read the small characters of the news headlines displayed on the screen. However, when the user tries to push, as a button, the text of a hyperlinked news headline or input characters though a software keyboard shown in FIG. 15(b), the user may have difficulty pushing a desired button because of a large difference between the finger size and the size of the buttons displayed on the screen.
The technologies relating to touch panels are evolving year by year, and not only touch panels that detect a touch manipulation as a user input manipulation but also touch panels that detect coming into proximity of a user finger as a user input manipulation are being developed. For example, the non-contact user input device disclosed in Patent document 1 is known which relates to a touch panel for detecting coming into proximity of a finger.
The non-contact user input device disclosed in Patent document 1 is configured so as to include plural linear transmission electrodes, a transmitter for supplying transmission AC currents to the respective transmission electrodes, plural linear reception electrodes disposed so as not to be in contact with the transmission electrodes, and a receiver for receiving AC currents that flow through the respective reception electrodes. Capacitors are formed at the crossing points of the transmission electrodes and the reception electrodes and capacitors are formed as a fingertip of the user comes closer to a touch panel. Therefore, the capacitances of the capacitors vary according to the degree of proximity of the finger. The non-contact user input device can recognize the distance between the touch panel and the finger on the basis of variations of the capacitances.